<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <li>1111</li>
    <li>2111</li>
    <li>3111</li>
</body>
<script>
    class jQuery {
        constructor(selector) {
            let elements = Array.from(document.querySelectorAll(selector));
            let length = elements ? elements.length : 0;
            for (let i = 0; i < length; i++) {
                this[i] = elements[i];
            }
            this.length = length;
        }
        html() {
          return '111'
        }
    }
    window.$ = function (selector) {
        return new jQuery(selector);
    }
    let html = $("li").html()
    console.log(html)
    const lenght = $("li").length
    console.log(lenght)
</script>

</html>